Identification and Protection of Series DC Arc Fault for Photovoltaic Systems Based on Fast Fourier Transform

Abstract

Nowadays, the development of renewable energy is increasing by many countries in the world, one of which is through the use of photovoltaic. By installing photovoltaic as a source of electrical energy, it is necessary to pay attention to the risks of hazards that arise, one of which is the series DC arc fault. Series DC arc fault cannot be detected by conventional safety device such as Circuit Breaker (CB), so special device is needed for photovoltaic systems, which can detect series DC arc fault and secure photovoltaic system by deciding current flow from photovoltaic to load when a series DC arc fault occur. Therefore, a series DC arc fault identification and protection device is designed, by utilizing a microcontroller and using the Fast Fourier Transform method to detect the presence of high frequency components at DC currents when a series DC arc fault occur, where the sum of high frequency components can be used as an algorithm for determining the series DC arc fault. The result shows that when the series DC arc fault occur, the current in the system decreases with a percentage decrease of 19.95% on average, and the sum of the spectrum values in the frequency range 0 to 12.5 kHz above 600. In securing the system, the device can works well, with the disconnection time of each test below the maximum allowed time in the UL 1699B, and has an average disconnection time of 0.67 seconds.